Citius, Altius, Fortius…

The sky’s no limit.

By Morand Fachot

"Faster, Higher, Stronger" – the Olympic motto could very well reflect the evolution of civil aviation. Planes are flying faster, higher and further than ever, as well as transporting more passengers, nearly 3 billion in 2012, with increasing safety. This has much to do with major advances in avionics, the electronic systems used in commercial, civil and defence aerospace applications. IEC TC (Technical Committee) 107 develops process management standards for avionics.

Flight engineer stations, such as this one, were made obsolete by advanced avionics

A huge market

Avionics represent a significant share of the cost of both commercial and defence aircraft, anywhere between 20% and 80% according to the type of plane. Sales of commercial aircraft are booming: no less than 1 460 units of all types were sold at the recent Paris Air Show.

In its Current Market Outlook 2013-2032 for the commercial aviation sector, the Boeing Company estimates that the demand for aircraft (from wide body to regional jets) over that period will exceed 35 000 units with a total value of over USD 4 800 billion.

From pioneers to international air transport

Commercial air transport started with mail services in Europe, the US and between continents soon after WW1 (World War 1). Services for fare-paying passengers were launched on short-haul flights on a very limited scale in the 1930s. Following WW2, the availability of large fleets of surplus advanced military aircraft, capable of carrying many passengers and freight over longer distances, helped kick-start international air transport. Initially this was on a limited scale due to relatively high costs.

In early air travel, aircraft were equipped only with basic instruments and pilots flew according to mainly visual flight rules.

Safety: a prime concern from the onset

Navigation, one of the most crucial factors in air safety, relied initially on a limited set of instruments that gave pilots indications of speed (airspeed and vertical speed indicators), altitude (altimeter), direction (magnetic and gyro compass) and used attitude indicators that showed the degree of bank (level wings) and pitch (nose up or down).

These instruments were particularly valuable in poor visibility conditions and gave air pressure and indications of magnetic or gyroscopic effects. They were liable to report inaccurate information due to imprecise calibration and adverse atmospheric conditions (e.g. ice might clog the pitot tubes used to determine airspeed) or magnetic effects (geomagnetic storms, changes in geomagnetic fields affecting compass).

Pilots also relied on other methods such as celestial navigation or dead reckoning, where an aircraft’s current position is calculated based on previous position, expected plane and wind speeds and other parameters, such as sightings of landmarks. These methods are notably subject to human error.

Other flight instruments such as dials and gauges were also indispensable for keeping pilots and crews informed about essential mechanical parameters on the aircraft, such as fuel levels, engine oil pressure and temperature.

Another important aspect of flight safety, communication with the ground, was introduced with the use of HF (high-frequency) shortwave radio in the 1930s. It is still in use today.

Into the modern age

Although some radio navigation techniques such as RDF (radio detection finding), which determines a position via triangulation, and other radio beam systems, were developed in the 1930s, the main technological innovations for air navigation were launched during WW2. Again, as often in the past, war proved a major technology accelerator, heralding advances in equipment, such as autopilot, which allowed the first transatlantic flight with automatic landing to take place in 1947.

Arguably the most significant innovation that found its way into civilian aviation applications after the war was radar detection. Radars were first installed in ground stations in Britain shortly before WW2 to provide long-range detection and tracking of enemy bombers. They were later fitted into military aircraft to find targets on the ground and in the air.

Another electronics-based device that was developed during the war was the transponder for IFF (identification, friend or foe) system. The SSR (secondary surveillance radar) system used in air traffic control is based on IFF.

These developments were introduced into civil aviation applications along with advances in the use of radio navigation systems using the VHF (very high frequency) band (108 to 117.95 MHz) deployed in VOR (VHF omnidirectional radio range) and led to major improvements in aircraft navigation.

After WW2, civilian aircraft, like their military counterparts from which they were often derived, allowed long-haul transport of passengers and freight. However, the added complexity of their various systems, such as multiple piston and jet engines, hydraulic and electrical equipment, meant constant monitoring of countless dials and gauges under the supervision of a flight engineer.

Safer flights

The use of radars and transponders in aircraft led to the introduction of other systems, such as airborne weather radar, which warns of severe weather conditions ahead of the aircraft, and lightning detectors.

TCAS (traffic alert and collision avoidance system), reducing the risk of mid-air collision, and GPWS (ground proximity warning system), helping prevent a normally functioning aircraft under the control of a properly trained crew from flying into the ground, are further examples of detection equipment that has been gradually installed into aircraft. The systems have greatly enhanced aviation safety. The ICAO (International Civil Aviation Organization) recommends or mandates that these systems are fitted to civilian aircraft of certain categories. Many different IEC TCs (Technical Committees) participate in the development of Standards for these technologies.

Aircraft navigation errors can lead to crashes and other tragic incidents. This was the case when KAL 007, a Korean Air Lines passenger flight from Anchorage to Seoul, was shot down by a Soviet Air Force fighter after it strayed over Soviet airspace in September 1983. This tragedy, in which 269 died, led US President Ronald Reagan to announce the same month that GPS (Global Positioning System), the US-developed satellite-based navigation system, would be made available for civilian use once it became operational, which it did in 1994.

The electronics revolution

The widespread and parallel introduction of avionics in the military and civilian sectors is a natural development of the integration observed in the aircraft industry. A small number of large companies (some now merged into others), such as Lockheed, McDonnell-Douglas or Boeing in the US, British Aerospace in the UK, Dassault Aviation in France, United Aircraft Corporation (Russia), EADS (European Aeronautic Defence and Space Company), or Embraer (Brazil), develop most of the world's civilian and military aircraft. Most of them participate actively in IEC work.

Their engineers frequently develop systems that are installed in both military and civilian aircraft. However, 80% of the avionics market is controlled by a very small number of OEMs (Original Equipment Manufacturers).

The development of avionics has been greatly accelerated by the widespread introduction of ICs (integrated circuits) that resulted in the availability of smaller and more powerful electronic equipment in general, as well as advances being made in other domains. One example is flat displays offering full colour graphics both at night and in full sunlight. Avionics now covers a very wide range of equipment that includes fly-by-wire systems, communications, flight controls, displays, flight management, aircraft sensors, data management, navigation and monitoring systems.

Enter the glass cockpit

As computers and electronic sensors started providing all the information pilots needed, it became more practical to replace arrays of multiple analogue mechanical dials and gauges with electronic displays. In particular, MFDs (multi-function displays) can show navigational, weather and other information from multiple systems if and when required.

Replacing analogue dials and gauges with digital units made it possible to have a so-called "glass cockpit" with a two-man flight deck, eliminating the need for a flight engineer. Furthermore, avionics allows families of aircraft to share the same basic glass cockpit, making it easier for crews to train and fly different aircraft.

Pilots now increasingly use electronic flight bags, the size of a laptop computer or smaller, which replace the traditional carry-on flight bags containing aircraft operating manual, flight-crew operating manual, navigational charts and other paper documents. Tablet computers can also be adapted for use as electronic flight bags.

IEC work crucial for avionics

Although they may be subjected to severe conditions such as the possible negative effects of atmospheric radiation at high altitude, or temperatures that may be outside the range specified for semiconductor devices by their manufacturers, avionics products must still perform reliably and safely during their working life.

IEC TC 107 develops process management standards for these and other issues. Avionics OEMs use increasing volumes of COTS (commercial off the shelf) electronic components, equipment and systems designed and manufactured for other industries in which they have limited control.

Many countries and regions are adopting legislation that restricts or eliminates the use of substances containing lead in most electrical and electronic equipment. As the avionics industry relies on COTS components, TC 107 provides a lead-free control plan that allows manufacturers to check the reliability of the components they use.

TC 107 has also set up a WG (Working Group) to provide guidance for the avoidance, detection and mitigation of counterfeit electronic parts in avionics applications.

IECQ, the worldwide approval and certification system for covering the supply of electronic components and associated materials and assemblies and processes, has a special scheme, ECMP (Electronic Component Management Plan), for avionics products.

Other IEC TCs, such as TC 47: Semiconductor devices, or TC 110: Electronic display devices, prepare International Standards for components used in avionics applications.

Contributing to the safety of a whole industry

In addition to new aircraft being equipped with avionics ("forward fit"), the retrofit of newer systems into existing aircraft adds value to the avionics market, which is worth billions of dollars.

IEC International Standards ensure this sector expands whilst offering authentic products that are reliable and safe during their required life.

Gallery

Flight engineer stations, such as this one, were made obsolete by advanced avionics

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The IEC (International Electrotechnical Commission) is the world’s leading organization that prepares and publishes International Standards for all electrical, electronic and related technologies. Close to 20 000 experts from industry, commerce, government, test and research labs, academia and consumer groups participate in IEC Standardization work.